JP4880723B2 - Resistive touch panel with press detection function - Google Patents

Description

  The present invention relates to a resistive touch panel having a pressure detection function for measuring a pressure of a direction component perpendicular to a surface among external forces applied to the surface.

  2. Description of the Related Art Conventionally, there is a screen input device in which, for example, a touch panel is overlaid on a display screen of an image display device such as a liquid crystal display and a button displayed on the display screen is selected by a pressing operation on the touch panel. The touch panel includes a resistance film type (for example, refer to Patent Document 1) and an optical type. Among these, the resistance film type touch panel is widely spread due to advantages such as a simple structure and low cost. Yes.

  The resistive touch panel detects the position where the transparent conductive films formed on the upper and lower panels are in contact as a change in resistance value, and is configured as shown in FIGS. This resistive touch panel is composed of a lower panel 50 and an upper panel 60 arranged to face each other. The lower panel 50 is formed by forming a transparent conductive film 52 such as ITO as a resistance film on almost the entire upper surface of the glass plate 51, and forming position detection electrodes 53a and 53b at both ends in the X direction in the figure. Further, the upper panel 60 is formed with a transparent conductive film 62 such as ITO as a resistance film on almost the entire lower surface of the flexible transparent resin film 61, and position detection electrodes 63a, 63b is formed. The lower panel 50 and the upper panel 60 are opposed to each other via a dot spacer 54 made of a transparent insulator as shown in an enlarged sectional view in FIG. The films 52 and 62 are entirely separated by an air layer (hereinafter referred to as an air gap).

 The electrode 53a of the lower panel 50 and the electrode 63b of the upper panel 60 are connected to a power source via switches SW1 and SW2, respectively. The electrode 53b of the lower panel 50 and the electrode 63a of the upper panel 60 are respectively connected to the switches SW3 and SW4. Is grounded.

 When the position of the point P on the upper panel 60 of the resistive touch panel is pressed, the transparent resin film 61 is bent and the upper and lower transparent conductive films 52 and 62 come into contact with each other. At this time, when the switches SW1 and SW3 are turned on and the switches SW2 and SW4 are turned off, the power supply voltage Vcc and the ground voltage are applied between the electrodes 53a and 53b, respectively. A voltage obtained by dividing the power supply voltage Vcc according to the X-direction position x is obtained. This is output to a detection circuit (not shown) as an X coordinate detection signal. Similarly, when the switches SW2 and SW4 are turned on and the switches SW1 and SW3 are turned off, the power supply voltage Vcc and the ground voltage are applied between the electrodes 63a and 63b, respectively. A voltage obtained by dividing the power supply voltage Vcc in accordance with the Y-direction position y is obtained. This is output as a Y coordinate detection signal to a detection circuit (not shown).

JP 2002-259057 A

  In recent years, in an electronic device having a touch panel, particularly a portable electronic device such as a mobile phone or a game machine, it is required to add a press detection function to the touch panel, for example, instead of a determination button. However, in the resistive film type touch panel of Patent Document 1, only the pressed position (X, Y coordinates) can be detected, and the pressed pressure (Z direction) cannot be detected.

  Further, since the resistive film type touch panel of Patent Document 1 is configured such that an air gap is entirely present between the upper and lower transparent conductive films, there is much reflection of light that occurs at the boundary with the air layer, and image display is performed. The visibility of the display part of the device was not good.

  In addition, as a material used for the upper and lower transparent conductive films, a material having good transparency, conductivity and durability such as ITO (indium tin oxide) was required. In addition to the resistive touch panel, organic EL panels, solar cells, The demand for ITO such as blue light-emitting diodes is expanding, and the problem of resource depletion has become serious because In (indium), which is the main component of ITO, is a rare metal. In view of the reserves of In resources, there is a prediction that if it continues to be used as it is, it will be depleted in 2011, increasing the sense of crisis. As a result, the price of In has continued to rise, making it difficult to provide touch panels at low cost.

  Therefore, an object of the present invention is to solve the above-mentioned problem, and not only the position of the pressed screen (X, Y coordinates) but also the Z direction (pressure) can be detected at the same time, and the visibility is excellent. An object of the present invention is to provide a resistive touch panel having an inexpensive press detection function.

  In order to solve the technical problem, the present invention provides a resistive film type touch panel having a press detection function having the following configuration.

According to the first aspect of the present invention, the first transparent conductive film is formed as the resistance film on the upper surface of the transparent plate, and the first position detection electrode pair is formed at both ends in the first direction of the first transparent conductive film. A first member formed of
A second transparent conductive film, which is a resistive film, is formed on the lower surface of the flexible transparent film, and second position detection electrode pairs are formed at both ends of the second transparent conductive film in a second direction orthogonal to the first direction. A second member formed by forming
The first and second transparent conductive films are superposed so as to face each other with a predetermined gap,
In a resistive touch panel that detects a pressing point based on the potential of the first and second electrode pairs for position detection,
The first member and the second member are bonded together with a transparent adhesive layer in which a large number of through holes are uniformly distributed between the first and second transparent conductive films,
Further, a conductive pressure-sensitive ink member that is disposed in each through hole and is formed on at least one of the opposing surfaces of the first member and the second member and whose electrical characteristics change due to the applied pressing force. With
A resistive film type touch panel having a pressure detection function is provided.

  According to the second aspect of the present invention, the pressure sensitive ink member is a dot having a diameter of 0.01 mm to 1 mm, and the pressure sensitive ink member in the through hole and the through hole has a pitch of 0.1 mm to 10 mm. A resistive film type touch panel having a press detection function according to the first aspect is provided.

  According to a third aspect of the present invention, the pressure sensitive ink member is disposed on the first member and has a pressure detection function according to any one of the first and second aspects. Provide a touch panel.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the pressure-sensitive ink member is in contact with both opposing surfaces of the first member and the second member. A resistive touch panel having the described pressure detection function is provided.

  According to a fifth aspect of the present invention, as described in any one of the first to fourth aspects, the through hole is formed with a diameter 0.05 to 2 mm larger than the pressure-sensitive ink member. A resistive touch panel having a press detection function is provided.

  According to the resistive touch panel having a pressure detection function according to the present invention, the first transparent conductive film and the second transparent conductive film are not brought into direct contact with each other at the pressing point, but are conducted through the pressure-sensitive ink member. I took. That is, when a load is applied to the pressure-sensitive ink member, the resistance value of the pressure-sensitive ink member decreases, and conduction is achieved. At this time, if the resistance value of the pressure-sensitive ink member exceeds a certain threshold value, it can be determined that the input is input, and the pressed position (if the first and second transparent conductive films are not in direct contact with each other) X, Y coordinates) can be detected. In addition, the Z direction (pressure) at that position can be detected simultaneously when the resistance value of the pressure-sensitive ink member decreases.

  Further, since the first member and the second member are bonded together by a transparent adhesive layer in which a large number of through holes are uniformly distributed between the first and second transparent conductive films, An air gap exists only in the through hole between the transparent conductive films. Therefore, there is little reflection of light that occurs at the boundary with the air layer, and the visibility of the display unit of the image display device is improved.

  Furthermore, if the pressure-sensitive ink member is durable, an inexpensive material that does not require durability can be used for the first and second transparent conductive films, and an inexpensive touch panel can be obtained. .

It is a typical disassembled perspective view of the main component part of the touch panel concerning one Embodiment of this invention. It is a model exploded perspective view of the decoration constituent part of the touch panel concerning one embodiment of the present invention. It is a schematic cross section of the touch panel concerning one Embodiment of this invention. It is a perspective view of the mobile telephone carrying the touch panel concerning one Embodiment of this invention. It is A1-A1 sectional drawing of FIG. It is sectional drawing which shows schematic structure of the conventional touch panel. It is a disassembled perspective view which shows schematic structure of the conventional touch panel. It is an expanded sectional view of the conventional touch panel.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic exploded perspective view of main components of a touch panel according to an embodiment of the present invention, and FIG. 2 is a schematic exploded perspective view of decorative components of the touch panel according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a touch panel according to an embodiment of the present invention. The touch panel 104 is connected to the lower panel 1 as the first member and the upper panel 2 as the second member, which are opposed to each other, and to the external circuit by being connected to the ends of the upper panel 2 and the lower panel 1. FPC 3 that forms a connector part for secure connection, transparent adhesive layer 4 for bonding the first member and the second member, and pressure-sensitive ink member 5 for detecting the position and the strength of the pressing force (See FIGS. 1 and 3). In this embodiment, the decorative film 6 and the hard coat shown in FIG. 2 are further formed on the surface opposite to the surface facing the lower panel 1 of the upper panel 2 by PSA (Pressure Sensitive Adhesive) 8 and 9. The film 7 is stuck in order to constitute the second member.

  The lower panel 1 is configured as follows. That is, a transparent conductive film 12 that becomes a resistance film (also called a transparent electrode) is formed on the upper surface of the transparent plate 11. In order to insulate the peripheral portion of the lower panel 1, the transparent conductive film 12 is formed on the entire surface by etching away the peripheral portion or covering it with an insulating layer. Conductive paste is formed as position detection electrodes (also called bus bars) 15a and 15b on the lower panel 1 at both ends facing in the X direction, and extends from these electrodes 15a and 15b to the FPC connection portion. The routing wirings 15c and 15d are formed.

  The transparent plate 11 is usually composed of a material excellent in transparency, rigidity, and workability, such as a glass plate, polymethyl methacrylate (PMMA) resin, polycarbonate (PC) resin plate 11A, and the like. Alternatively, as shown in FIG. 1, a transparent resin film 11 </ b> B, for example, a PET film, a PC film, or the like may be bonded to the upper surface with PSA 10.

  Examples of the material of the transparent conductive film 12 include metal oxides such as tin oxide, antimony oxide, zinc oxide, and cadmium oxide, and conductive polymer thin films. If the pressure-sensitive ink member 5 is durable, these transparent materials that do not require durability can be used for the transparent conductive film 12.

  As a method for forming the transparent conductive film 12, for example, a vacuum deposition method, sputtering, ion plating, a CVD method, a roll coater method, or the like can be used. The etching can be performed by forming a resist by a photolithography method, a screen method, or the like in a portion to be left as an electrode and then immersing in an etching solution such as hydrochloric acid. In addition, after the formation of the resist, the etching is performed by spraying an etchant to remove a portion of the conductive film where the resist is not formed, and then immersing in a solvent to swell or dissolve the resist and remove it. Can also be done. The etching can also be performed with a laser.

  As the conductive paste for forming the electrodes 15a and 15b and the lead wirings 15c and 15d, a metal such as gold, silver, copper, or nickel, or a paste such as carbon can be used. Examples of these forming methods include printing methods such as screen printing, offset printing, gravure printing, or flexographic printing, and photoresist methods.

  On the other hand, the upper panel 2 is configured as follows. That is, a transparent conductive film 22 that becomes a resistance film (also referred to as a transparent electrode) is formed on the lower surface of the flexible transparent resin film 21. In order to insulate the peripheral portion of the upper panel 2, the transparent conductive film 22 is formed on the entire surface by etching away the peripheral portion or covering it with an insulating layer. Conductive paste is formed as position detection electrodes (also referred to as bus bars) 25a and 25b on the upper panel 2 at both ends facing in the Y direction, and extends from these electrodes 25a and 25b to the FPC connection portion. The lead wires 25c and 25d are formed.

  The flexible transparent resin film 21 is made of, for example, a resin such as PET or PC.

  The conductive paste for forming the transparent conductive film 22, the electrodes 25a and 25b, and the routing wirings 25c and 25d is the same as described for the lower panel 1.

  The FPC 3 forming the connector part is formed by forming terminals 32a, 32b, 32c, 32d made of conductive patterns on one surface of an insulating resin film 31 made of PET or the like. These terminals 32a, 32b, 32c, 32d are respectively The lead wires 15c, 15d, 25c, and 25d are connected to each other by, for example, a conductive adhesive.

  Terminals 32a and 32c from the electrodes 15b and 25b are connected to a power source Vcc through switches SW1 and SW2 (not shown), respectively. Terminals 32b and 32d from the electrodes 15a and 25a are grounded via switches SW3 and SW4 (not shown), and are connected to terminals for X coordinate detection and Y coordinate detection of a detection circuit (not shown).

  In the above embodiment, one end of the FPC 3 is inserted and connected between the upper panel 2 and the lower panel 1, but a through hole is provided in the lower panel 1 and the connection is made through the through hole. You may make it do.

  The transparent adhesive layer 4 for bonding the first member and the second member is configured as follows. That is, a large number of through-holes 4a are uniformly distributed, have adhesiveness, adhere the first member and the second member, and maintain a gap between the transparent conductive films 12, 22. This is an insulating member. Therefore, it is not necessary to provide dot spacers in the present invention. As the transparent adhesive layer 4, for example, a punched double-sided adhesive tape without a core material can be used. The thickness of the transparent adhesive layer 4 is set to 0.01 to 2 mm, for example.

  Since the first member and the second member are bonded together by the transparent adhesive layer 4 having a large number of through holes 4a, an air gap exists only in the through holes 4a between the upper and lower transparent conductive films 12 and 22. Therefore, there is little reflection of light that occurs at the boundary with the air layer, and the visibility of the display unit of the image display device is improved.

  Each through hole 4a is more preferably formed to have a diameter larger by 0.05 to 2 mm than each pressure-sensitive ink member 5. By increasing the thickness by 0.01 mm or more, the transparent adhesive layer 4 and each pressure-sensitive ink member 5 do not overlap even if a positional deviation occurs in the bonding of the transparent adhesive layer 4. Further, by preventing the size from exceeding 2 mm, it is possible to more reliably prevent the transparent conductive films 12 and 22 from being energized without passing through each pressure-sensitive ink member 5, and the through-hole 4a Inconspicuous.

  The pressure-sensitive ink member 5 for detecting the position and the strength of the pressing force is configured as follows. That is, the composition constituting the pressure-sensitive ink member 5 that is arranged in each through-hole 4a of the transparent adhesive layer 4 and whose electric characteristics change due to the applied pressing force is an electric resistance according to an external force. It is made of a material whose electrical characteristics such as value change. As the composition, for example, a quantum tunneling composite material available under the trade name “QTC” from Peratech of England can be used. As a method for forming the pressure-sensitive ink member 5, a printing method such as screen printing, offset printing, gravure printing, or flexographic printing can be used.

  Each pressure-sensitive ink member 5 is preferably a dot having a diameter of 0.01 mm to 1 mm, and the through holes and the pressure-sensitive ink members in the through holes are preferably arranged at a pitch of 0.1 mm to 10 mm. If the pitch is less than 0.1 mm, it is difficult to recognize the image of the screen located on the back surface. Further, when the pitch exceeds 10 mm, the detection accuracy is lowered.

  The pressure-sensitive ink member 5 may be formed on at least one of the opposing surfaces of the first member and the second member, and more preferably, the lower member that is the first member as in the present embodiment. This is the side panel 1 side. This is because the upper panel 2 is easily stressed by bending.

  Furthermore, it is more preferable that the pressure-sensitive ink member 5 is in contact with both opposing surfaces of the first member and the second member. This is because detection is possible from a light input load. When an air layer is left between the first member and the second member in each through hole 4a of the transparent adhesive layer 4, the distance between the air layers is 0.5 mm at the maximum for the above reason.

 When the position of the point P on the upper panel 2 is pressed, the transparent resin film 21 is bent and an external force is applied to the pressure-sensitive ink member 5 sandwiched between the transparent conductive films 12 and 22 near the point P. The resistance value of the pressure-sensitive ink member 5 to which the external force is applied changes, and the upper and lower transparent conductive films 12 and 22 are conducted through the pressure-sensitive ink member 5. At this time, when the switches SW1 and SW3 are turned on and the switches SW2 and SW4 are turned off as in the prior art, the power supply voltage Vcc and the ground voltage are applied between the electrodes 15a and 15b. Is obtained by dividing the power supply voltage Vcc according to the position x of the point P in the X direction. This is output to a detection circuit (not shown) as an X coordinate detection signal. Similarly, when the switches SW2 and SW4 are turned on and the switches SW1 and SW3 are turned off, the power supply voltage Vcc and the ground voltage are applied between the electrodes 25a and 25b, respectively. A voltage obtained by dividing the power supply voltage Vcc in accordance with the Y-direction position y is obtained. This is output as a Y coordinate detection signal to a detection circuit (not shown). The input is determined when the resistance value of the pressure-sensitive ink member 5 exceeds a certain threshold value. Otherwise, there is a problem that erroneous input such as a lost hand or a handle occurs.

  After detecting the pressed position (X, Y coordinates), the switches SW2 and SW2 are turned on, the switches SW1 and SW4 are turned off, and the power supply voltage Vcc and the ground voltage are respectively applied between the electrodes 25a and 15b. give. When the position of the point P is pressed, the pressure-sensitive ink member 5 interposed in the conduction of the upper and lower transparent conductive films 12 and 22 near the point P causes the lower pressure-sensitive ink to increase as the applied external force increases. Since the electric resistance value of the member 5 becomes small, the current flowing between the upper and lower transparent conductive films 12 and 22 increases when the pressing force to the touch input surface to the touch panel increases. By detecting this change in current converted into a voltage value, the external force applied to the pressure-sensitive ink member 5 can be detected, and the pressure applied to the touch input surface of the touch panel can be detected.

  By the way, the touch panel shown in the present embodiment preferably functions as a touch input device for a display of an electronic device, in particular, a portable electronic device such as a mobile phone or a game machine. An example in which a touch panel is mounted on a mobile phone is shown.

  4 is a perspective view of a mobile phone equipped with a touch panel according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line A1-A1 of FIG.

  As shown in FIG. 4, the mobile phone 101 includes a synthetic resin casing 102 having a display window 102 </ b> A formed on the front surface and a display unit 103 </ b> A such as a liquid crystal display or an organic EL, and is incorporated in the casing 102. The image display device 103, the touch panel 104 fitted in the display window 102A, and a plurality of input keys 105 arranged on the front surface of the housing 102 are provided.

  The display window 102 </ b> A of the housing 102 is formed to have a step to allow the touch panel 104 to be fitted. An opening 102a is formed on the bottom surface of the display window 102A so that the display 103A of the image display device 103 can be seen. The touch panel 104 is disposed on the frame-like portion 102b around the opening 102a and closes the opening 102a (see FIG. 5). A double-sided tape 107 or the like can be used for fixing the touch panel 104.

  Note that the shape and size of the display window 102 </ b> A can be variously changed according to the shape and size of the touch panel 104. The level difference of the display window 102 </ b> A can be variously changed according to the thickness of the touch panel 104. The shape and size of the opening 102a of the display window 102A can be variously changed according to the shape and size of the display portion 103A. Here, the shape of the display window 102A, the opening 102a, the display unit 103A, and the touch panel 104 is rectangular, and the height of the step of the display window 102A is the same between the surface of the housing 102 and the surface of the touch panel 104. It is set.

  In the touch panel 104 of the present embodiment, as described above, the decorative film 6 and the hard coat film 7 are sequentially attached to the surface opposite to the surface facing the lower panel 1 of the upper panel 2 by the transparent adhesive. And constitutes the second member. Therefore, as shown in FIG. 4, it has 104 A of transparent window parts, and the frame-shaped decoration area | region 104B arrange | positioned around 104 A of transparent window parts. When the touch panel 104 is arranged in the display window 102A of the casing 102 of the mobile phone, the display unit 103A of the image display device 103 can be viewed from the transparent window portion 104A.

  The decorative film 6 shown in FIG. 2 is formed by applying ink in a frame shape on the peripheral surface of a transparent resin film similar to the upper panel 2. The decoration area 104B of the touch panel 104 is formed by a decoration portion 6a that is a portion where the ink is applied, and a portion (non-decoration portion) 6b where the decoration portion 6a is not provided is a transparent window portion 104A of the touch panel 104. It becomes.

  As the ink constituting the decorative portion 6a, polyvinyl chloride resin, polyamide resin, polyester resin, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd A colored ink containing a resin such as a resin as a binder and an appropriate color pigment or dye as a colorant may be used. Moreover, the decoration part 6a may be formed by printing instead of application | coating. When forming the decoration part 6a by printing, normal printing methods, such as an offset printing method, a gravure printing method, and a screen printing method, can be utilized.

  The hard coat film 7 is made of, for example, polyethylene terephthalate (PET) resin or polyimide.

  In addition, for the bonding of the transparent plate 11, the bonding of the upper panel 2 and the decorative film 6, and the bonding of the decorative film 6 and the hard coat film 7, acrylic resin, epoxy resin, phenol Insulating PSA 8, 9, 10 made of resin or vinyl resin is used.

  In the above embodiment, the decorative film 6 is provided for the configuration shown in FIG. 5, but the decorative film 6 is provided when the bezel is used to cover the peripheral edge of the touch panel. It does not have to be.

  The present invention can detect not only the position (X, Y coordinates) of the pressed screen but also the Z direction (pressure) at the same time, so that it is useful for electronic devices, particularly portable electronic devices such as mobile phones and game machines. It is.

1 Lower panel 2 Upper panel 3 FPC
4 Transparent adhesive layer (perforated)
4a Through-hole 5 Pressure-sensitive ink member 6 Decorative film 6a Decorative part 6b Non-decorative part 7 Hard coat film 8, 9, 10 PSA
DESCRIPTION OF SYMBOLS 11 Transparent board 12 Transparent electrically conductive film 15a, 15b Position detection electrode 15c, 15d Lead wiring 21 Transparent resin film 22 Transparent conductive film 25a, 25b Position detection electrode 25c, 25d Lead wiring 50 Lower panel 51 Glass plate 52 Transparent conductive film 53a, 53b Position detection electrode 54 Dot spacer 60 Upper panel 61 Transparent resin film 62 Transparent conductive film 63a, 63b Position detection electrode 70 Frame adhesive layer 100 Mobile phone 102 Housing 102A Display window 103 Image display device 103A Display unit 104 Touch panel 104A Transparent window portion 104B Decorating area 105 Input key 107 Double-sided tape

Claims (5)

A first member formed by forming a first transparent conductive film as a resistance film on the upper surface of the transparent plate and forming first position detection electrode pairs at both ends in the first direction of the first transparent conductive film;
A second transparent conductive film, which is a resistive film, is formed on the lower surface of the flexible transparent film, and second position detection electrode pairs are formed at both ends of the second transparent conductive film in a second direction orthogonal to the first direction. A second member formed by forming
The first and second transparent conductive films are superposed so as to face each other with a predetermined gap,
In a resistive touch panel that detects a pressing point based on the potential of the first and second electrode pairs for position detection,
The first member and the second member are bonded together with a transparent adhesive layer in which a large number of through holes are uniformly distributed between the first and second transparent conductive films,
Further, a conductive pressure-sensitive ink member that is disposed in each through hole and is formed on at least one of the opposing surfaces of the first member and the second member and whose electrical characteristics change due to the applied pressing force. With
A resistive touch panel having a pressure detection function. The pressure-sensitive ink member is a dot having a diameter of 0.01 mm to 1 mm, and the through-hole and the pressure-sensitive ink member in the through-hole are arranged at a pitch of 0.1 mm to 10 mm.
A resistive touch panel having a press detection function according to claim 1. The pressure-sensitive ink member is disposed on the first member;
A resistive touch panel having a pressure detection function according to claim 1. The pressure-sensitive ink member is in contact with both opposing surfaces of the first member and the second member;
A resistive touch panel having a press detection function according to claim 1. The through hole is formed with a diameter 0.05 to 2 mm larger than the pressure-sensitive ink member.
A resistive touch panel having a press detection function according to any one of claims 1 to 4.

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